9a frass in second half of the in well isolated, not too small grains; larva: anterior spiraculum with two equal arms, with a total of about 10 papilla: Phytomyza hendeli

9b frass in second half of the mine in fine grains that lie close together, often also in pearl chains or short strings; front spiraculum with two unequal arms, with about 12 papillae (rarely on this hostplant): Phytomyza ranunculi